storing high scores??

Java on Mobile Devices J2ME
#1

Hey i’ve got a pacman type game and i’m wondering if i can store the highest scores in the phones memory… i’ve searched around and found the RMS functions but it seems like an awful lot of code just to store say the top 5 or 10 highest scores in the phone? Is there a simpler way of doing this or will i have to study RMS?

Thanks

RSYR

#2

[quote=“RSYR,post:1,topic:35162”]
Yup!
It’s not that hard though - if I recall there’s a few easy examples to google for.

#3

Thanks for the quick reply!! I’ll give it a go in the morning. Cheers

#4

okay so i’ve got some code and its kind of working but i’m having trouble…
I want to retrieve my enumerated scores from the database and print them to a string…
but this only seems to be setting the latest score. It does work in the output bar as println but not when i put it to string.


package game;

import javax.microedition.lcdui.Alert;
import javax.microedition.lcdui.AlertType;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.TextField;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;
import javax.microedition.rms.RecordComparator;
import javax.microedition.rms.RecordEnumeration;
import javax.microedition.rms.RecordStore;

public class HighScore extends MIDlet implements CommandListener
{
	TextField name, score;
	Command add, show, exit, home;
    private String HS;
    private Form f;


	protected void destroyApp(boolean arg0) throws MIDletStateChangeException
	{
		// TODO Auto-generated method stub

	}

	protected void pauseApp() {
		// TODO Auto-generated method stub

	}

	protected void startApp() throws MIDletStateChangeException
	{
		f = new Form("High scores");

		f.append(name = new TextField("Name", "", 255, TextField.ANY));
		f.append(score = new TextField("Score", "", 10, TextField.NUMERIC));

		f.addCommand(add = new Command("Add new score", Command.OK, 1));
		f.addCommand(show = new Command("Retrieve scores", Command.OK, 2));
		f.addCommand(exit = new Command("Exit", Command.EXIT, 1));

		f.setCommandListener(this);

		Display.getDisplay(this).setCurrent(f);
	}
	public void commandAction(Command c, Displayable d)
	{		
            if(c == home)
		{
		Display.getDisplay(this).setCurrent(f);
		}
		if(c == exit)
		{
			notifyDestroyed();
		}
		else if(c == add)
		{
			try
			{
				addNewScore(name.getString(), score.getString());

				showConfirm("Score correctly added");
			}
			catch(Exception e)
			{
				showError(e.toString());
			}
		}
		else if(c == show)
		{
			try
			{
				String[][] scores = retrieveHighScores();

				System.out.println("HIGH SCORES");

				for(int i = 0; i < scores.length; i++)
				{
					System.out.println("SCORE: " + scores[i][0] + " - " + scores[i][1]);
                                        HS = ("SCORE: " + scores[i][0] + " - " + scores[i][1]);
                                }
				showConfirm("Scores correctly retrieved");
			}
			catch(Exception e)
			{
				showError(e.toString());
			}
		}
	}
	void showConfirm(String text)
	{
        Display.getDisplay(this).setCurrent(new Alert("Score Added", text, null, AlertType.CONFIRMATION));
        Form highscore = new Form("Your Score");
        highscore.append(HS);

	highscore.addCommand(home = new Command("Home", Command.OK, 1));
        highscore.addCommand(exit = new Command("Exit", Command.EXIT, 1));

        highscore.setCommandListener(this);
        Display.getDisplay(this).setCurrent(highscore);
	
	}
	void showError(String error)
	{
		Display.getDisplay(this).setCurrent(new Alert("Error", error, null, AlertType.ERROR));
	}

	void addNewScore(String name, String score) throws Exception
	{
//		 We open the recordstore
		RecordStore highscore = RecordStore.openRecordStore("High Score", true);

//		 To add a new HiScore we use a quick string comma-separated
		String str = new String(name + "," + score);
		byte [] strb = str.getBytes();
		highscore.addRecord(strb, 0, strb.length);

		highscore.closeRecordStore();
	}
	String[][] retrieveHighScores() throws Exception
	{
		String[][] scores;

		RecordStore highscore = RecordStore.openRecordStore("High Score", true);

//		 To read all hiscores saved on the RMS
		RecordEnumeration enumerator = highscore.enumerateRecords(null, new ScoresComparator(), false);
		int id, index, separator;
		byte[] record;
		String str;

		index = 0;

		scores = new String[enumerator.numRecords()][2];

		while (enumerator.hasNextElement( )) {
		     id = enumerator.nextRecordId( );
		     record = highscore.getRecord(id);
		     str = new String(record);
		     // Operate with str to extract name and points

		     separator = str.indexOf(',');

		     scores[index][0] = str.substring(0, separator);
		     scores[index][1] = str.substring(separator + 1);

		     index++;
		}
		highscore.closeRecordStore();

		return scores;
	}


	class ScoresComparator implements RecordComparator
	{
		public int compare(byte[] arg0, byte[] arg1)
		{
			int score0 = 0, score1 = 0;

			for(int i = 0; i < arg0.length; i++)
			{
				if(arg0[i] == ',')
				{
					score0 = Integer.parseInt(new String(arg0, i + 1, arg0.length - i - 1));
				}
			}
			for(int i = 0; i < arg1.length; i++)
			{
				if(arg1[i] == ',')
				{
					score1 = Integer.parseInt(new String(arg1, i + 1, arg1.length - i - 1));
				}
			}

			if(score0 < score1)
				return 1;
			else if(score0 == score1)
				return 0;
			else
				return -1;
		}
	}
}

Any Help Appreciated Cheers

#5

http://www.j2meforums.com/forum/

will almost certainly have example code and tips.
Used to be there all day when I used to make J2ME stuff. Good site.